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Subject: Re: [PHP-DEV] Allow dropping typehints during inheritance
From: smalyshev@gmail.com (Stanislav Malyshev)

Hi!

> If we allow larger type, why doesn't such code work ?
> 
> interface A { }
> interface B extends A { }
> 
> class C {
>     public function foo(A $a) { }
> }
> 
> class D extends C {
>     public function foo(B $a) { } // E_STRICT
> }
> 
> This is wrong IMO.

This shouldn't work - it means that if you have D object, you should be
able to call foo on it with any A parameter. However, your definition
says not every A parameter would work, but only one that is actually B
(i.e. class that implements A but not B is not going to work anymore).
That means D violates C's contract by rejecting some calls that C accepted.

-- 
Stas Malyshev
smalyshev@gmail.com